Li Yunhui, Wu Ziyan, Ma Nan, Gao Junping
Department of Ornamental Horticulture, China Agricultural University, 100094, Beijing, China.
Plant Cell Rep. 2009 Feb;28(2):185-96. doi: 10.1007/s00299-008-0629-3. Epub 2008 Nov 5.
Our previous work has indicated that an ethylene-responsive aquaporin gene, Rh-PIP2;1, played an important role in the epidermal cell expansion of rose petals. In this work, we isolated an 896 bp promoter sequence of the Rh-PIP2;1 and found that the promoter was rare in plants, occurring with an Inr motif, but without a TATA box. In transgenic Arabidopsis harboring the Rh-PIP2;1 promoter::GUS construct, the activity of Rh-PIP2;1 promoter was found to be developmental-dependent in almost all of the tested organs, and was particularly active in organs that were rapidly expanding, and in tissues with high water flux capacity. Moreover, the promoter activity was inhibited by ACC, ABA, NaCl, and cold in the roots of 3 or 6-day-old plants, and was increased by GA(3) and mannitol in the rosettes of 9 or 12-day-old plants. Deleting the fragment from -886 to -828 resulted in nearly complete disappearance of the promoter activity in roots, and a substantial decrease in the leaves, hypocotyls and floral organs. Taken together, our results indicated that the Rh-PIP2;1 promoter responded to hormones and abiotic stresses in a developmental- and spatial-dependent manner, and the -886 to -828 region was crucial for the activity of the Rh-PIP2;1 promoter.
我们之前的研究表明，一个乙烯响应水通道蛋白基因Rh-PIP2;1在玫瑰花瓣的表皮细胞扩张中发挥重要作用。在本研究中，我们分离得到了Rh-PIP2;1的一段896 bp的启动子序列，发现该启动子在植物中较为罕见，含有一个Inr基序，但没有TATA框。在携带Rh-PIP2;1启动子::GUS构建体的转基因拟南芥中，发现Rh-PIP2;1启动子的活性在几乎所有测试器官中都具有发育依赖性，并且在快速扩张的器官以及具有高水通量能力的组织中特别活跃。此外，3日龄或6日龄植株根中的启动子活性受到乙烯利、脱落酸、氯化钠和低温的抑制，而9日龄或12日龄植株莲座叶中的启动子活性则因赤霉素和甘露醇而增强。删除-886至-828片段导致根中启动子活性几乎完全消失，叶片、下胚轴和花器官中的活性也大幅下降。综上所述，我们的结果表明，Rh-PIP2;1启动子以发育和空间依赖的方式对激素和非生物胁迫作出响应，-886至-828区域对Rh-PIP2;1启动子的活性至关重要。
